Steerprop Ltd. Azimuth Propulsors

Steerprop Ltd. produces azimuth propulsors for the maritime industry and for the offshore oil and gas industries.
Steerprop Ltd. concentrates on the single product line. It provides a customer with the superb quality and lifetime economy he expects and deserves.

A New Generation of Azimuth Propulsors

The development of the Steerprop Azimuth Propulsor range – a totally new generation of azimuth propulsors – started from a blank piece of paper. Using the combined experience of the Steerprop Team (more than 180 years of azimuth thruster industry) as well as a mass of input and feedback from vessel owners, superintendents, shipyards and naval architects the principal philosophy and basic design was set.

Power Range

Steerprop Propulsors are available in the propulsors size range from SP 10 to SP 80 and in power range from approx 500 kW to approx. 6500 kW. Propulsors for higher power are normally custom-made according to project specific requirements.
The Steerprop power range is optimized to correspond to the market demand and to suit a variety of vessels, applications and operational profiles including the ice breakers fir the Arctic application.


Basic Philosophy

To achieve an outstanding lifetime, economy, the design and construction of the Steerprop Azimuth Propulsors are based on the following principal criteria: reliability, performance, flexibility and ecological compatibility.

Electric Steering Motors

Steerprop propulsors are equipped with a modern frequency converter controlled steering system, comprising direct electric steering motors – hydraulic motors are available as an option.

The use of electric motors offer the following advantages:
constant steering speed
less power required
less power loss / better efficiency
less heat generation — less cooling
less piping
less noise
less maintenance


Pressurised Lubrication System

The gears and bearings in the upper gearbox are pressure lubricated, combined with an ejector based oil level control, keeping the oil level constant irrespective of oil temeprature. This enables a better control of the lubrication as well as improves the efficency of the unit thanks to smaller friction, resulting in less power loss and heat generation.


Triple Steeringtube Seals

The steering tube is sealed using triple lip seals, installed with stainless steel liners to minimize wear. The outermost seal is turned downwards to minimize collection of dirt that may wear out the seals. The triple seal assembly enables the facility to flush the seal chamber of propeller shaft seals


Fabricated Steel Structure

The Steerprop Propulsor housing is made of fabricated steel. Utilising the properties of the steel a precise strength control as well as a constant quality is achieved. It also allows for faster delivery times and size flexibility. Fabricated steel is easy to maintain and repair, in case of an accident to the unit.

FlushFluid Shaft Seals

The propeller shaft is sealed using either triple or quadruple ring-type, seals. The space between the seals is filled with a seal fluid under pressure against sea water / lubrication oil . The pressure is provided with either a header tank or a pressurized tank. The sealing fluid can be monitored and flushed.

High Performance Noozle

Steerprop uses its own in-house designed high-performance nozzle, the HJ3. The nozzle is designed to provide an 8-10% increase in bollard pull, but also an increase in maximum efficiency of 10-15% compared to standard type nozzles. The propeller is situated in the diffusor part of the nozzle, comparably far aft, enabling the nozzle to be installed close to the pivoting axis of the propulsor, thus, minimizing steering torque.

Few Propritary Parts

Steerprop propulsors are equipped with a multi-disc clutch with slipping facility. As an option this facility may be utilised by electronic control and increased cooling to provide a controlled propeller speed between zero and prime mover idle speed.


Keyless Shrink-fit Joints

All joints in the power train are either conical or cylindrical shrink fit joints. There are no keyways to deteriorate the integrity of the shafts, nor keys that may wear and break.

Number of Parts Minimized

The Steerprop R&D engineers have succeeded to minimize the amount of parts in the construction of Steerprop propulsors. This simplified and more reliable construction leads to easier maintenance and less spare parts.


Compact Propulsor Size

The Steerprop propulsors have been designed to be as compact as possible. This enables azimuth propulsors also to be used on vessel designs with low main decks, with little space beneath.

Sequential Strenght Principle

Steerprop propulsors are engineered with an in-built security in both the housing and the power train. This comprises a sequential strength principle, where the weakest parts are either cheap or easily replaced – important in case of an accident. In the power transmission the weakest component is a blade of the propeller, thus protecting valuable and hard to access components of the powertrain. Within the overall strength of the housing structures attention is also paid to safety: the bolted flange in the steering tube above the propeller is dimensioned to break in a controlled manner in case of an overwhelming impact, e.g. grounding.